Enantioselective Synthesis of α‐Alkylmalates as the Pharmacophoric Group of Several Natural Alkaloids and Glycosides

Abstract A general enantioselective synthesis of α‐alkylmalates found in Cephalotaxus and Orchidaceae species is described. This preparation is based upon Seebach’s procedure for the alkylation of D ‐malic acid with self‐regeneration of stereogenic centers. Reaction of the dioxolanone 8a with LiHMDS and allyl halides as well as benzyl bromide gave 10 and 14 , respectively, which could be transformed into enantiopure α‐alkylmalates 13 , 15 , 18 and 19 . In addition, enantiopure furans of type 20 have been prepared. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)